Code Layering Accounts (#4882)

* code layering for accounts

* formatting

* formatting

* formatting

src/sql/platform/accounts/common/accountPickerViewModel.ts

@@ -0,0 +1,47 @@
+/*---------------------------------------------------------------------------------------------
+ *  Copyright (c) Microsoft Corporation. All rights reserved.
+ *  Licensed under the Source EULA. See License.txt in the project root for license information.
+ *--------------------------------------------------------------------------------------------*/
+
+import * as azdata from 'azdata';
+import { Event, Emitter } from 'vs/base/common/event';
+
+import { IAccountManagementService } from 'sql/platform/accounts/common/interfaces';
+import { UpdateAccountListEventParams } from 'sql/platform/accounts/common/eventTypes';
+
+/**
+ * View model for account picker
+ */
+export class AccountPickerViewModel {
+	// EVENTING ////////////////////////////////////////////////////////////
+	private _updateAccountListEmitter: Emitter<UpdateAccountListEventParams>;
+	public get updateAccountListEvent(): Event<UpdateAccountListEventParams> { return this._updateAccountListEmitter.event; }
+
+	public selectedAccount: azdata.Account;
+
+	constructor(
+		private _providerId: string,
+		@IAccountManagementService private _accountManagementService: IAccountManagementService
+	) {
+		// Create our event emitters
+		this._updateAccountListEmitter = new Emitter<UpdateAccountListEventParams>();
+
+		// Register handlers for any changes to the accounts
+		this._accountManagementService.updateAccountListEvent(arg => this._updateAccountListEmitter.fire(arg));
+	}
+
+	// PUBLIC METHODS //////////////////////////////////////////////////////
+	/**
+	 * Loads an initial list of accounts from the account management service
+	 * @return {Thenable<Account[]>} Promise to return the list of accounts
+	 */
+	public initialize(): Thenable<azdata.Account[]> {
+		// Load a baseline of the accounts for the provider
+		return this._accountManagementService.getAccountsForProvider(this._providerId)
+			.then(undefined, () => {
+				// In the event we failed to lookup accounts for the provider, just send
+				// back an empty collection
+				return [];
+			});
+	}
+}